package offer;

public class offer_0010_2 {
    public int numWays(int n) {
        if(n==0||n==1) return 1;
        int[] dp=new int[n+1];
        dp[0]=1;
        dp[1]=1;
        for(int i=2;i<=n;++i){
            dp[i]=(dp[i-1]+dp[i-2])%1000000007;
        }
        return dp[n];
    }
}
